The present invention relates to a new and improved construction of buoyancy balance of the type equipped with a buoyant or floating body floating in a fluid and a load bowl or scale operatively coupled with such buoyant body.
Balances of this type are based upon the physical principle, also known as Archimedes' principle, that a body immersed in a fluid undergoes a decrease in weight which corresponds to the weight of the fluid displaced by such body. A major advantage of such balances resides in the fact that they can be constructed practically free of mechanical friction.
Balances of the type under discussion have already become known to the art in many different constructional embodiments, as exemplified for instance by German Pat. Nos. 5931 or 335,786 relating to upper-bowl balances, Swiss Pat. No. 74,648 or U.S. Pat. No. 2,544,032 relating to lower-bowl balances. All of the state-of-the-art balances have common thereto a characteristic feature, namely, during a movement of the load bowl or scale, as such is brought about by a change in the load, the immersion depth of a displacement body changes for such length of time until the increase in load is compensated by the gain in buoyancy. The aforementioned displacement body generally is constituted by an element which interconnects the buoyant body with the load bowl, directly or however indirectly, i.e. through the agency of a rod, and such element is generally in the form of a pressure rod which piercingly extends through a boundary surface of the fluid. Since this element must possess for mechanical reasons (strength) a minimum cross-section which is dependent upon the maximum weight (dead load and weighing range), the sensitivity of the balance, that is to say, the change in the immersion depth for each unit of load change, is dependent upon the total weight and therefore such sensitivity is relatively low.